dsol has it pegged. Check shore power. It is unlikely any other breakers or GFI in TT have tripped.
You probably have a 50 amp 240 volt service in your 5th wheel. What do you have it plugged into. A 15 amp home outlet will be easily overloaded unless you practice sever power management.
Electric water heating or electric refrigerator are off limits. Use propane.
A big battery charger working hard and a microwave at the same time will trip the shore circuit breaker. Air conditioning with anything else at the same time is off limits.
GFI refers to "Ground Fault Interrupter". It trips when even tiny stray currents are detected.
Circuit Breakers trips when current exceeds circuit breaker rating.
Fuses are similar to Circuit Breakers. They blow out when current exceeds rating.
There are circuit breakers with built in GFI. They will trip when either stray current or high current is present.
I wish you good luck and happy trails ahead!